Data and conclusions on the potential harmful effects of oral creatine supplementation in healthy individuals was discussed in a study by HJ Kim, et al. In thus article it was reviewed that healthy subjects supplemented with creatine, liver and kidney function did not appear to change in both young and older populations. Excess creatine ingestion however, is a burden to be eliminated by the kidney and even if there are no obvious health risks associated with oral creatine supplementation it is best to err on the side of caution when supplementing on a chronic basis. The authors advise that high-dose (over 3-5 g/day) creatine supplementation of over 3-5 grams per day should not be used by anyone with pre-existing kidney disease or those with a potential risk for renal dysfunction (diabetes, hypertension, reduced glomerular filtration rate). In conclusion, analysis of kidney function prior to creatine supplementation should be considered for safety reasons but in healthy subjects appears unnecessary. (19)
